A known lance holder for an oxygen lance comprises a retaining body, a gripping head to hold the lance fixed and a slag run-back safety device mounted in the retaining body of the lance holder between the lance and an oxygen-supply hose.
A lance holder with a suitable gripping head and a slag run-back safety device acts to hold the lance required for refining safely and to prevent slag run back on ending or interruption of the blowing process from reaching the oxygen-supply hose.
In the lance holder according to German Open patent application 23 27 595 a gas permeable disk made of sintered metal, which prevents the slag run back, is mounted just in front of the oxygen-supply hose. This mechanical closure for the slag run back is not satisfactory when comparatively large quantities of oxygen must be provided. Then the use of the sintered metal disk leads to problems depending on its nature.
Slag run back safety devices are also known which have valve cones movable relative to each other. In these safety devices the appropriate valve cone is pressed into a sealing surface when slag comes into contact with the valve cone to prevent the flow of slag.
Problems are also noted with these safety devices when the lance by error or by force is released or loosened so that the oxygen-supply hose end and the lance holder loaded with flowing oxygen can come into contact. Danger to operating personnel then exists. This is especially true for lances of large diameter in which the weight of the lance can result in an unsatisfactory securing of the lance by the gripping head and expose personnel to danger as mentioned above.